Screw-propeller.



G. H.' NITSCHKE. SCREW PROPELLER., APPUCATiON HLED OCT. 21 1911.

Patented July 17, 1917.

2 SHEETS-SHEET 11 G. H. NITSCHKE.

SCREW PRUPELLER.

APPLICATION HLED OCT. 21. 1911.

Patented July 17 1917 2 $HEETSSHEET Z blades slightly .enonen HENRYNITSOHKE, or COLUMBUS, OHIO.

SCREW-PROPELLER.

To all whom it may concern:

Be it known that I, GEORGE HENRY NITSCHKE, a citizen of the UnitedStates, residing at Columbus, in county of Franklin and State of Ohio,have invented certain new and useful Improvements in Screw- Propellers,of which the following is a specification.

My invention relates to an improvement in screw propellers for water andaerial navigation and for ventilating purposes, and the object is toattain a maximum speed witha minimum expenditure of power, and arelatively low rate of revolutions.

In short, this invention consists in means for accomplishingmechanically what a fish does in swimming, the principle of action ofthe two being one and the same; and to this end it comprises primaryblades which di- Verge from the central shaft in a tangential positioncoming to a more or less sharp angle at their ends in connection withsupplemental blades extending outwardly from the primary blades in adirection approximating a right angle, and terminating at their oppositeouter ends in more or less acute angles, both primary and secondaryblades located at equidistant points from each other on the centralshaft, and disposed obliquely to a plane transverse or at right anglesto the axis of rotation.

My invention further consists in certain novel features of constructionand combinations of parts which will be hereinafter fully described andpointed out in the claims.

In the accompanying drawings Figure 1 is a view of the stern portion ofa vessel showing my improved propeller attached,

Fig. 2 is an enlarged view of the propeller shown in Fig. 1,

Fig. 3 is a transverse section through the shaft looking rearwardly froma position forward of the propeller, and

Fig. 4 is a similar view showing the curved instead of straight, as inthe other forms illustrated.

The numeral 1 designates the propeller shaft, and 2 is a hub rigidlysecured thereon from which the primary blades 3, 3, diverge. Theseblades are peculiar in design, being straight at the rear edge a fromend to end and in the form ol an obtuse angle e be tween. the cutting}edges Z and (a so that at Specification of Letters Patent.

Application filed October 21, 1911.

Patented Jul 17, 1917.. Serial No. 655,855.

the extreme outer end they are in the form.

of a sharp or acute angle d.

Secondary blades 4, 4, are preferably similar in design to the primaryblades, eX- cept that the edge 7) corresponding to edge 6 of the primaryblade is disposed nally across and integral with the widest portion ofthe primary blade, extending from the obtuse angle diagonally rearward,with the edge 0 corresponding to the edge 0 of the primary bladeextending outwardly ployed, and in this connection it might be mentionedthat the propeller may be built of wood, metal, or fiber, according tothe work it is designed to perform. It may be constructed in a solidpiece, orin sections,

, so that if one part should become broken,

it could be replaced.

lVhile my experiments have shown an ad vantage in straight blades orpaddles as illustrated in Figs. 1, 2, and 3, it is obvious that theymight be more or less curved, as illustrated in Fig. 4, withoutdeparture from the main features of my invention.

Also while I have not illustrated it, it is equally obvious that theblades might be disposed in just the reverse direction, or as if theshaft 1 were reversed endwise.

In action the propeller rotates as indicated by the arrow in Fig. 3. Thesharp angles of the blades or paddles first enter and part the watergradually, thus with the least resistance to the rotary action of theshaft, whereupon the pressure increases upon the water, pushingbackwardly upon it with violence, and in so doing pushing the water fromthe blades, one blade always following another interrupting the suctionand repeating the action and the blades at equidistant positionson theshaft balancing and equalizing the strain.

It will be observed that both the primary and secondary blades orpaddles are always presented to the resisting wall of water or to theair at an inclination so that a continuous and increasing push orpressure is exerted upon the medium in which the propeller is revolvingfrom one end of each blade to the other, after which, instead ofcatching and holding the medium, it is per mitted'to slide off withoutany retardation of the propulsive action of the propeller.

Thus With a propeller of this character, I am enabled to cheapen the"cost and increase the speed of either water or aerial navigation.

Inaddition to the advantage of increased speed,I have found by actualexperiments that a propeller of this type steadies the boat, and holdsit and causes it to travel horizontally in the Water,.which in itself isa desideratum.

It is evident that more or less slight changes'lmi'ghtl beresorted. toin the form and arrangement of the several parts .describedwithoutdeparture from the-spirit andzscope of rhyinvention, and hence I do notvvishito be limited to the exact construction-herein set forth, but

20 Having; ifully described my invention,

What-I claim as new and desire tosecure by Letters Patent, 1s

1. A PI'OPGl'lQP COmPHSHIg a hub, a main blade having a forward rake,and a second-- =aryv' blade havinga pitch, attached thereto intermediateof the: hub: .portionand 'tip of theimainblade, the" secondary bladehaving. a backward rake."

2. A propeller-comprising a hub, a main Oopifiihithis {patent-may beobtained fer intermediate of the hub portion and tip of the main blade,the secondary blade having a backward rake, and of such a length as toextend rearwardly beyond the primary blade.

3. A propeller comprising a hub, a main blade having a forward rake, anda secondary blade having a pitch, attached thereto intermediate of thehub portion and tip of the main blade, the secondary blade having abackward rake, and of such a length as to extend forwardly of theprimary blade.

at. A propeller comprising a hub, a main blade having a forward rake,and a secondary blade having a pitch, attached thereto intermediate ofthe hub portion and tip of the main blade, the secondary blade having abackward rake,-and' of such-a. length as to extend beyond the primaryblade in either direction.

In testimony whereof I aflix niy signature, in'the presence of twowitnesses.

GEORGE HENRY NITSC'HKE.

Vitnesses:

J. D. YOAKLEY, LLOYD W. PATCH.

five-cents each, by addressing the -Commissioner-of Patents, Washington,D. C.

